Why not columns that contain tables? It would certainly make things easier. e.g. Get a list of customers with their orders:

SELECT ... FROM customers LEFT JOIN orders ...;

To get this into a presentable table, I would have to keep track of the previous customer's ID and only start a new row if the current customer ID is not equal to the previous customer ID. If table-valued columns were available, each customer row would have a column containing a table of their orders.